The field of this invention relates to reinforcement for convoluted stretch hoses or conduit, and more specifically to reinforcements that assists in producing a helical valley in the hose or conduit during manufacturing and later use.
Prior art convoluted helical shaped stretch hoses and conduits, are well known. Adding reinforcement to the stretch hose is less well known because of the difficulty of reinforcing a convoluted shaped hose. Even less well known is the use of bidirectional reinforcement on a stretch hose which appears to have only been taught by the Applicant in U.S. Pat. No. 6,948,527, issued on Sep. 27, 2005, titled: “Pressure-Actuated Linearly Retractable and Extendible Hose”, and U.S. Pat. No. 7,549,448, issued on Jun. 23, 2009, titled: “Linearly Retractable Pressure Hose”. Also, patent application Ser. No. 10/303,941 filed Nov. 25, 2002 and its resulting Divisional patent application Ser. No. 11/234,944 filed Sep. 26, 2005 by the Applicant, do not teach forming neither a u-shaped valley nor a v-shaped valley with cord reinforcements that is parallel to the helical valley of the convoluted hose.
The thin wall construction of a stretch hose does not easily allow reinforcement to be applied. The convoluted helical shape is what allows these hoses to extend to many times their retracted length and consistently retract under their own spring power. For these hoses to self-retract easily, they can be designed with a thin walled body that is indented between coils, or expanded between the coils, to allow the hose body to extend and retract without binding against itself. Because of these physical limitations on the thickness and flexibility of the hose body, most prior art stretch hoses can only withstand pressures of about 5 Pounds per Square Inch (psi) for extended periods of time at room temperature and less at higher temperatures. Thus, some type of reinforcement is required to prevent rupture of this type of stretch hose when used with typical compressed air and household water pressures. Further, the shape of the valley portion of the convoluted hose is a factor in determining the hose's retracting ability and strength. The disclosed fiber reinforcement is applied in the valley of a convoluted stretch hose to provide one or more of the following functions: 1) to provide radial pressure strength for the hose, 2) to provide a means for shaping the hose valley into a predetermined shape, and 3) to substantially maintain the position of the valley during use and to insure the proper shape for retracting after extended use.
While many prior art stretch hoses discuss “reinforcement” for their hoses, the Examiner should understand that they are generally talking about the helical wire as the “support” or “reinforcement” against crushing, not a flexible fiber reinforcement in the helical valley of the hose to resist internal pressure. The “wire reinforcement” in prior art designs keep the hose bore from collapsing and from crushing and kinking during use, but provide little internal pressure support for resisting internal hydraulic or pneumatic pressure. The disclosed valley reinforcement provides significant pressure support for the disclosed stretch hoses, which helps stabilize the shape of the hose to insure proper extending and retracting operation.
The convoluted helical shape of a stretch hose does not led itself easily to the addition of reinforcement because of the uneven shape of the surface with its helical peak and valley. Some reinforced conduits have been built, but are made with flat sheet material that is thin enough that the sheet material can crumple under force to allow the conduit be retracted. Such conduits are generally used with a compression spring which is used to keep the hose extended for use, and user must apply force to retract the hose. Most self-retracting stretch hoses, are made from a single extruded strip of elastomer material that can be stretched over the helical wire support and rolled to form the convoluted shaped stretch hose. As soon as bidirectional reinforcement is added, problems arise because the reinforcement material can not deform with the elastomer hose material. Thus, the reinforcement strongly resists any reshaping that might be required to form the convoluted shape. Thus, prior art methods of reinforcement for cylindrically shaped hoses do not work when applied to a convoluted helical stretch hose shape. Wrapping, weaving, and knitting methods of reinforcing a convoluted hose have difficulty forming and holding the proper shape for the valley of the hose, though some methods for forming a u-shaped valley are disclosed in Divisional application Ser. No. 11/234,944. Preferably the valley can be v-shaped to allow easy extending and retracting of the hose, while also reducing stresses in longitudinal reinforcement. In other configurations, more rounded u-shaped hose valleys can be used for specific hose designs.
The use of the disclosed helical valley reinforcement solves many of the problems with maintaining the shape of the valley by providing a continuous coated yarn reinforcement placed near the center of a convoluted hose valley and/or on the walls of the valley. The yarn reinforcement can be wound in the valley of the hose and over other longitudinal and radial reinforcements. The tension on the valley reinforcement yarn prevents tension in the longitudinal yarn reinforcement from significantly deforming the valley from the desired v-shape. The yarn or cord reinforcement in other configurations can also be placed along the entire valley wall to maintain the v-shape. Thus, knitted or wrapped fiber reinforcement is forced to form a v-shaped valley by properly tensioning one or more yarns of high-strength fibers near the center of the hose valley to define the radius of the hose at the center of the valley. This process of wrapping reinforcement yarn or cord in the valley of the convoluted hose can be done by simply feeding the reinforcement yarn into the hose valley as the hose rotates pass. Such a method of valley reinforcement can produce finished hose or conduit at a rate of about one foot per second.